Synthesis and characterization of stilbene derivatives for possible incorporation as smart additives in polymers used as packaging films

Article abstract of DOI:10.1071/C96180

Several series of stilbene derivatives for possible use as smart additives in polymers used as packaging films have been prepared and characterized. Differential scanning calorimetry was performed on some of the stilbenes in order to determine any liquid crystal properties. Those compounds which had multiple phase transitions were also shown to have two liquid crystalline phases according to optical microscopy.

Full text of DOI:10.1071/C96180

C S I R O P U B L I S H I N G
Australian Journal
of Chemistry
Volume 50, 1997
© CSIRO Australia 1997
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Aust. J. Chem., 1997, 50, 425–434
Synthesis and Characterization of Stilbene Derivatives
for Possible Incorporation as Smart Additives in
Polymers Used as Packaging Filmsꢀ
Gary M. Day,A Owen T. Howell,A Michael R. Metzler B
and Paul D. Woodgate B,C
A
Industrial Research Limited, P.O. Box 2225, Auckland, New Zealand.
Department of Chemistry, University of Auckland,
B
Private Bag 92019, Auckland, New Zealand.
C
Author to whom correspondence should be addressed.
Several series of stilbene derivatives for possible use as smart additives in polymers used as packaging
ꢀlms have been prepared and characterized. Diꢁerential scanning calorimetry was performed on some
of the stilbenes in order to determine any liquid crystal properties. Those compounds which had
multiple phase transitions were also shown to have two liquid crystalline phases according to optical
microscopy.
Introduction
Preparation of the Stilbene Derivatives
One of the limitations of polymer ꢀlms currently
used for modiꢀed-atmosphere packaging is their limited
permeation characteristics under varying environmen-
tal temperatures. Ideally, changes in the permeation
rates of carbon dioxide and oxygen with tempera-
ture should be similar to the corresponding changes
in respiration rate of the produce contained within.
It has been shown previously that incorporation of
liquid crystalline materials into a polymer matrix can
improve dramatically the gas permeability properties
of the ꢀlm.1 However, the transition temperatures
involved in the reported cases were considerably above
refrigeration temperatures. We have sought to address
this problem by the use of liquid crystalline additives
having transition temperatures slightly higher than
typical storage temperatures (0–10ꢀC). These liquid
crystalline compounds would also need to be non-
toxic since they will ultimately be in contact with
the fresh produce. From the numerous compounds
prepared previously,2 it was thought that stilbenes
may best suit the requirements of having liquid crys-
talline properties at low temperatures, especially if
the structure included either branched alkyl chains
or multisubstituted aromatic rings. Moreover, these
compounds would have the added advantage of being
potentially non-toxic. Therefore several series of sub-
stituted stilbenes were synthesized and examined for
possible liquid crystal phase changes at temperatures
close to those used for refrigeration.
The synthesis of this class of compounds based
entirely on a hydrocarbon skeleton, namely the 1-
(3,5-dialkylphenyl)-2-(4-alkylphenyl)ethene series, was
investigated. The most direct synthesis of a library of
these stilbenes, which are meta-dialkylated in one of
the aromatic rings, is via 1,3,5-tribromobenzene (1a),
which has been trisfunctionalized by the sequential
exchange of each bromide by using BuLi/Et2O and
reaction at each step with Me3MIVCl (MIV = Si, Ge,
Sn).3 Furthermore, 3,5-dibromophenyllithium has been
coupled with CO2, ꢂuorinated esters, and ketones to
give the resultant acylated adducts in good yield.4
For the present purpose, this route intended to use
two sequential replacements of an aromatic bromide
by treatment with butyllithium, each resultant aryl
anion being trapped with an alkyl iodide to generate
compounds of the type (1b) and then type (1c) bearing
diꢁerent hydrocarbon side chains (R1 and R2). Further
treatment of the bromobenzene (1c) with BuLi followed
by reaction with dimethylformamide and hydrolytic
workup was expected to generate the formyl derivative
(1d). This aldehyde can then undergo a Wittig reaction
by treatment with the ylide formed from a suitably sub-
stituted p-alkylbenzyltriphenylphosphonium salt; this
should lead directly to the desired stilbene derivatives
(1e).
However, even after extensive experimentation involv-
ing the variation of a wide range of reaction parameters,5
treatment of (1a) with butyllithium in diethyl ether
ꢀ
This paper is dedicated to Professor R. C. Cambie on the occasion of his retirement.
Manuscript received 25 September 1996
0004-9425/97/040425$05.00
10.1071/CH96180

426
G. M. Day et al.
at ꢀ78ꢀC followed by reaction with iodomethane,
or 1-iodobutane, or 1-iodohexane aꢁorded only 1,3-
dibromobenzene (1h). When tetrahydrofuran was used
as solvent a complicated mixture was obtained from
which only (1a), (1h) and 1-alkyl-2,4,5-tribromobenzene
(from lithium–hydrogen exchange rather than lithium–
bromide exchange) could be identiꢀed.4
Clearly an alkyl transfer reagent more eꢃcient than
an iodoalkane is required in order to allow coupling
with the anion generated from (1a). A number of acyl
transfer reagents such as acid chlorides, anhydrides
and esters were therefore investigated.6 Although these
would lead to the formation of aromatic ketones rather
than arylalkane derivatives it was expected that sub-
sequent reduction (e.g. Clemmensen) of the benzylic
carbonyl could be achieved easily to form the required
compounds (1c). Not unexpectedly, when an acid
R
R1
R2
Br
R3
Br
Br
Br
(1b)
R1
R1
R2
(1a)
(1f)
(1g)
(1h)
(1i)
Br
CH=O
Br
H
H
CH
CH
C4H9
H
Br
R2
H
(1c)
R1
CH=CH2
H
(1j) CH=CHC2H5
(1k) CH=CHC4H9
(1l) CH=CHC5H11
(1m) CH=CHC6H13
H
H
R1
R2
H
(1e)
H
(1n)
(1u)
CH2OH
CO2H
H
H
R2
H
(1d)
O
Br
Br
Br
(1a)
(i) BuLi/Et2O
(ii) RCOCl or RCO2Et
O
R
Br
Br
+
+
+
R
R
Br
Br
Br
OCOR
Br
Br
Br
OH
(1h)
(2a) R = CH3
(2b) R = C5H11
Br
Br
Br
Br
(4a) R = CH3
(3a) R = CH3
(4b) R = C5H11
(3b) R = C5H11
Scheme 1
R2
R1
CH
CHR2
R1
R2
R2
Br
CH
CHR2
R1
CH
CHR2
R1
H
R2
R1
H
R2
C2H5
R1
CH3
(5a)
(5b)
(5c)
(5d)
(5e)
(5f)
(5g)
(5h)
C2H5
C2H5
C4H9
C4H9
C5H11
C5H11
C6H13
C6H13
(6a)
(7a)
C4H9
CH=O
H
(6b) CH=O C2H5
(6c) C4H9
(6d) CH=O C4H9
(6e) C6H13
(7b) CH2OH C4H9
(7c) CH=O C4H9
H
CH=O
H
(7d)
CH3
C6H13
H
(7e) CH2OH C6H13
(7f) CH=O C6H13
CH=O
H
(6f) CH=O C6H13
(6g) CO2H C6H13
(7g)
CH3
C8H17
CH=O
(7h) CH2OH C8H17
(7i) CH=O C8H17
(5i) CH=CHC2H5 C2H5
(5j) CH=CHC4H9 C4H9
(5k) CH=CHC6H13 C6H13

Stilbene Derivatives
427
H
O
chloride was used as electrophile the crude mixture
contained only a small amount of the desired ketone (2),
the alcohol (3) and its corresponding ester (4) being the
major products. Compound (3) is clearly the product
from reaction of (2) with 3,5-dibromophenyllithium;
the alkoxide of (3) may react further in situ with 1
mol. equiv. of the acid chloride to give the ester (4)
(Scheme 1).
Br
(i) BuLi
(ii) Me2NCHO
(iii) H3O+
Br
Br
Br
Br
(1f)
R1CH2PPh3+ I–
base
(1a)
R1CH PPh3
Br
A range of experiments was carried out in attempts
to deꢀne the optimum conditions required for the
formation of the desired ketones (2). In particular,
changes to the reaction temperature, transmetallation
of the aryllithium with either copper(I) bromide7 or
manganese(II) bromide,8 excess of acid chloride, and
inverse addition techniques, were investigated. Even-
tually the reproducible isolated yield of the aromatic
ketones (2a) and (2b) was increased, but to only 50–60
and 25–30%, respectively. The latter yield is clearly
ineꢃcient for the start of a multistep synthesis. When
an alkyl ester (RCO2C2H5, R = CH3 or C5H11) or
a symmetrical anhydride [(C5H11CO)2O] was used as
electrophile, again only mixtures of (1h) and (2)–(4)
were isolated, the highest yields of (2a) and (2b) being
42 and 32%, respectively.
Br
(i) BuLi
(ii) Me2NCHO
H
H
(iii) H3O+
H
Br
O
R1
H
R1
H
(1p)
(1o)
R2CH2PPh3+ I–
base
R2CH PPh3
H
O
Br
(i) BuLi
(ii) Me2NCHO
(iii) H3O+
H
H
H
H
H
H
R2
H
R1
R2
H
R1
In an alternative and successful approach the
route outlined in Scheme 2 was undertaken. This
sequence again relies on metal–halogen exchange of
1,3,5-tribromobenzene (1a) with butyllithium, the resul-
tant monoanion being trapped with dimethylformamide
to give, after hydrolytic workup, the formyl derivative
(1f). The use of dimethylformamide as electrophile
avoids the undesired formation of a ketone and prod-
ucts of its further reaction. Compound (1f) can
now undergo a Wittig reaction to give the alkenyl
derivative (1o). Repetition of this sequence for the
two bromine atoms remaining on the aromatic ring,
including a step to hydrogenate the alkene double
bonds, should lead to the 1-(3,5-dialkylphenyl)-2-(4-
alkylphenyl)ethene derivative (1t). It was recognized
that the classic Wittig reaction conditions with a
non-stabilized ylide would aꢁord a mixture of E and
Z isomers of the product stilbenes. However, the
simplicity of the method was attractive, and samples
of the pure stereoisomers could be separated chromato-
graphically, potentially allowing individual assessment
of each for liquid crystalline properties.
(1q)
(1r)
R3C6H4CH2PPh3+ I–
base
reduction
O
R3
R3C6H4CH
PPh3
H
CH
CH
R2CH2CH2
CH2CH2R1
(1s)
R2CH2CH2
CH2CH2R1
(1t)
Scheme 2
the desired dibromo aldehyde (1f) in 95% yield.4 Wittig
reactions10 have been carried out by using a wide range
of bases and solvents. The choice of solvent was critical
to the yield of the 3,5-dibromo alkene in the present
work; in diethyl ether the alkyltriphenylphosphonium
salts were only sparingly soluble and their deprotona-
tion with BuLi did not go to completion, leading to low
yields of the expected products. The use of ButOK–
ButOH solvate in diethyl ether is beneꢀcial to the yield
of some Wittig reactions.11 However, use of this solvate
for the generation of C6H13CH=PPh3 and its coupling
with (1f) did not lead to increased yields (31%) of the
product (1m). Moreover, 3,5-dibromobenzenemethanol
(1n) (43%) was also formed by hydride transfer from
the ylide. Although Bigot et al.12 have reported
the formation of Wittig products when the reaction
was carried out in either methanol or dioxan with
K2CO3 as base, treatment of C7H15PPh3+ Iꢁ/K2CO3 in
Therefore, a number of phosphonium salts of
the type RCH2PPh3+ Iꢁ required for the ꢀrst two
Wittig steps were synthesized [R = H (93%), C2H5
(93%), C3H7 (91%), C4H9 (82%), C5H11 (98%),
C6H13 (99%)] by treatment of the correspond-
ing alkyl iodide with triphenylphosphine. The 4-
alkylbenzyltriphenylphosphonium iodides required for
the ꢀnal Wittig step were synthesized9 from commer-
cially available 4-alkylbenzaldehyde diethyl acetals in
excellent overall yields (Scheme 3).
Treatment of (1a) with BuLi/Et2O at ꢀ78ꢀC fol-
lowed by quenching with dimethylformamide aꢁorded

428
G. M. Day et al.
methanol with 3,5-dibromobenzaldehyde (1f) returned
only starting material. However, treatment of (1f) with
C7H15PPh3+ Iꢁ/BuLi in tetrahydrofuran aꢁorded the
desired alkenyl dibromo derivative (1m) as a clear oil
in 95% yield.
of 56% from (1a). Hydrogenation of the oleꢀnic groups
in (12) over Pd/C aꢁorded 1-(3,5-dioctylphenyl)-2-(4-
ethylphenyl)ethane (13) (98%). This compound was
isolated as a clear oil which showed the molecular
ion at m/z 434 (C32H50), gave correct microanalytical
data, and had 1H and 13C n.m.r. spectra consistent
with the proposed structure.
OEt
O
H
OEt
OH
H
CH
CHC6H13
H3O+/CH2Cl2
NaBH4/MeOH
14 h
C2H5
CH
CH
R
R
R
(12)
CH
CHC6H13
C8H17
R
Yield
R
Yield
(8a) C2H5
(9a) C2H5 98%
(9b) C4H9 94%
(9c) C6H13 99%
(9d) C8H17 93%
(8b) C4H9 98%
(8c) C6H13 99%
(8d) C8H17
C2H5
CH2CH2
(13)
C8H17
Me3SiCl/NaI
MeCN/N2
2 h
Having shown that a 3,5-bis(alkenyl)benzaldehyde
does undergo Wittig coupling in good yield, we inves-
tigated methods of reducing the two double bonds in
the subtended groups without destroying the aldehyde
functionality. Hydrogenation of (6f) over Pd/C for 45
min aꢁorded not only the desired aldehyde (7i) (23%)
but also the methyl derivative (7g) (7%), and the
hydroxymethyl derivative (7h) (70%). The alcohol (7h)
was then reoxidized with pyridinium chlorochromate to
give aldehyde (7i) (89%); this sequence aꢁords (7i) in an
overall yield of 85% from (6f). When the hydrogenation
of (6f) was stopped after 2 mol. equiv. of hydrogen had
been consumed a complicated mixture of products was
obtained, including (1H n.m.r.) compounds containing
one double bond and a partially reduced aldehyde
group, as well as the expected products. With the
above hydrogenation/reoxidation sequence being used,
(7c) and (7f) were each synthesized in 89% yield from
their respective precursor, (6b) and (6d).
The aldehydes (7c), (7f) and (7i) were coupled
with the ylides generated by treatment of (8a),
(8b), (8c) and (8d) with BuLi. Typically, the 4-
alkylbenzyltriphenylphosphonium salts were treated
with 1 mol. equiv. of BuLi in tetrahydrofuran at 0ꢀC
for 5 min, resulting in the formation of a deep red
solution of the ylide. A solution of the aldehyde (7c),
(7f) or (7i) in tetrahydrofuran was then added and
the mixture was stirred at room temperature for 14 h,
resulting in decolorization. Workup and chromato-
graphy aꢁorded a mixture (85–90%) of the E (14a–j)
and Z (15a–j) isomers of a 1-(3,5-dialkylphenyl)-2-(4-
alkylphenyl)ethene. The fractions were contaminated
with a mixture of the E (16a–d) and Z (17a–d) isomers of
their corresponding 1,2-bis(4-alkylphenyl)ethene deriva-
tives. Analytically pure samples of all four components
were obtained by repetitive p.l.c. on silica gel with
hexanes as eluent. The 1,2-bis(4-alkylphenyl)ethene
derivatives were shown to form by coupling of a
PPh3+ I–
I
PPh3/C6H6
heat c. 5 h
R
R
R
Yield
R
Yield
(11a) C2H5 99%
(11b) C4H9 93%
(11c) C6H13 98%
(11d) C8H17 97%
(10a) C2H5 98%
(10b) C4H9 93%
(10c) C6H13 97%
(10d) C8H17 98%
Scheme 3
Reaction of (1m) with BuLi/Et2O at ꢀ78ꢀC followed
by coupling with dimethylformamide gave the formyl
derivative (5h) (89%), the yield depending critically on
the molar ratio of BuLi used in the halogen exchange
reaction. When 1ꢁ05 mol. equiv. of BuLi were used the
yield of the aldehyde decreased dramatically (20–40%),
the small excess of BuLi promoting competitive allylic
deprotonation and then polymerization of the alkene.
The second Wittig reaction to form the bis(alkenyl)-
aryl bromide (5k) from the aldehyde (5h) was achieved
in 96% yield by using the optimized procedure indicated
earlier. The key intermediate (6f) was then synthesized
(92%) by treatment of (5k) with BuLi/Et2O followed
by trapping of the anion with dimethylformamide and
hydrolytic workup. The 3,5-bis(alkenyl)benzaldehydes
(6f) showed the molecular ion at m/z 326 with an accu-
rate mass measurement that was correct for C23H34O,
and had H and 13C n.m.r. data that were consistent
1
with the proposed structure.
The mixture of E and Z isomers of the bis(alkenyl)-
aldehyde (6f) was coupled with 4-C2H5C6H4CH=PPh3
in tetrahydrofuran to aꢁord a mixture of the isomeric
stilbenes (12) (78%); this corresponds to an overall yield

Stilbene Derivatives
429
4-alkylbenzylidenetriphenylphosphorane ylide with a
4-alkylbenzyltriphenylphosphonium iodide. Since the
ylides were generated from the salts in the presence
of a base (BuLi), the formation of the by-products
could not be avoided.
H
R
(16b) R = C4H9
(16c) R = C6H13
(16d) R = C8H17
R
H
R2
R2
Table 1. Phase transition temperatures and enthalpies for the
liquid crystalline compounds (16b–d)
H
H
H
Symbols: K, crystalline phase; S, smectic phase; N, nematic
C
C
C
C
phase; I, isotropic phase
R1
R1
Cpd
R
K
S
N
I
H
Transition temperatures (ꢁC)
(16b)
(16c)
(16d)
C4H9
C6H13
C8H17
22
31
110B
96
A
R1
11
44C
R1
R1
46C
96
R1
R2
R2
Transition enthalpies ꢀH (J gꢂ1
)
A
D
(14a) C4H9 C2H5
(14b) C4H9 C4H9
(14c) C4H9 C6H13
(14d) C4H9 C8H17
(14e) C6H13 C2H5
(14f) C6H13 C4H9
(14g) C6H13 C6H13
(14h) C6H13 C8H17
(14i) C8H17 C4H9
(14j) C8H17 C6H13
(15a) C4H9 C2H5
(15b) C4H9 C4H9
(15c) C4H9 C6H13
(15d) C4H9 C8H17
(15e) C6H13 C2H5
(15f) C6H13 C4H9
(15g) C6H13 C6H13
(15h) C6H13 C8H17
(15i) C8H17 C4H9
(15j) C8H17 C6H13
(16b)
(16c)
(16d)
C4H9
3ꢀ5
20ꢀ6E
C6H13
C8H17
40ꢀ5
9ꢀ4
30ꢀ9
34ꢀ8
49ꢀ9E
A
Could not be determined.
Determined from optical microscopy.
Peak temperatures recorded due to broad overlapping peaks.
Not recorded since determination of transition was by optical
B
C
D
microscopy.
E Partial transition enthalpies recorded due to broad overlapping
peaks.
R
R
A by comparison of optical textures with those of
other materials of known smectic A composition. The
4,40-dibutyl derivative (16b), however, exhibited very
unusual behaviour. D.s.c. traces for this compound
reproducibly displayed only one transition between
ꢀ100 and +100ꢀC. The transition enthalpy for this
peak (3ꢁ5 J gꢁ1) was not large enough to be a melting
transition [cf. ꢄH values for (16c,d) in Table 1 for K–S
transitions]. Subsequently it was discovered by using
optical microscopy that this ꢄH appeared to indicate
a smectic to nematic transition. The exact nature of
the smectic phase could not be identiꢀed. Another
unusual feature of the 4,40-dibutyl derivative (16b) was
the absence of a liquid crystalline to isotropic transition
in the d.s.c. traces. Typically these transitions have
a rather large enthalpy value [Table 1, ꢄH values for
(16c,d)]. Further d.s.c. traces for compound (16b) were
run from ꢀ120 to +300ꢀC, but only the one phase
transition was exhibited. It was expected that, if a
liquid crystalline to isotropic transition did exist in
the temperature range examined, it would have been
seen, especially since a possibly nematic phase existed.
Surprisingly, the onset of the isotropic phase at 110ꢀC
could be seen clearly by optical microscopy, and at
120ꢀC compound (16b) was completely isotropic in
nature. That a transition from a liquid crystalline
phase to an isotropic phase existed but was not detected
by d.s.c. is extremely unusual.
H
H
H
C
C
C
C
H
R
R
(16a) R = C2H5
(16b) R = C4H9
(16c) R = C6H13
(16d) R = C8H17
(17a) R = C2H5
(17b) R = C4H9
(17c) R = C6H13
(17d) R = C8H17
Thermal and Optical Characterization
All of the stilbene derivatives prepared were examined
for liquid crystallinity by means of diꢁerential scanning
calorimetry (d.s.c.) between the temperatures of ꢀ100
and +100ꢀC. Surprisingly, the only compounds which
exhibited any liquid crystalline behaviour were the E
by-products (16b–d) of the coupling reaction between
the respective aldehydes and ylides. The phase transi-
tion temperatures and the transition enthalpies (ꢄH )
are listed in Table 1. All other stilbene derivatives were
liquid at ambient temperature. These results illustrate
the diꢃculty that exists in predicting structure–activity
correlations in potential liquid crystalline materials.
The actual phases of these liquid crystalline mate-
rials (16b–d) were determined by means of optical
microscopy. All three of these stilbene derivatives
exhibited both smectic and nematic phases (Table 1).
For the 4,40-dihexyl and 4,40-dioctyl derivatives (16c,
d) the type of smectic phase was identiꢀed as smectic
Further work in this area will involve mixing (either
through solutions or a melt) the liquid crystalline
compounds (16b–d) in various ratios, either with each
other or with some of the non-liquid crystalline stilbene

430
G. M. Day et al.
22ꢀ26, (CH2)4CH2CH3; 28ꢀ82, (CH2)2CH2C3H7; 30ꢀ93,
derivatives. The aim will be to obtain eutectic mixtures
with transitions that fall in the desired temperature
range (0–10ꢀC). Initial work on some mixtures has
indicated signiꢀcant lowering of some of the phase
transition temperatures.
CH2CH2C4H9; 31ꢀ54, (CH2)3CH2C2H5; 36ꢀ10, CH2C5H11
;
128ꢀ96, 2C, C 3 and C 5; 129ꢀ76, 2C, C 2 and C 6; 134ꢀ32, C 1;
150ꢀ35, C 4; 191ꢀ83, CH=O.
4-Hexylbenzenemethanol (9c)
Sodium borohydride (3ꢀ56 g, 93ꢀ7 mmol) was added in
ꢁve equal portions to a solution of 4-hexylbenzaldehyde (8c)
(10ꢀ0 g, 37ꢀ5 mmol) in methanol (100 ml) cooled to 0ꢁC. After
1 h at 0ꢁC the reaction mixture was allowed to warm to room
temperature and was stirred for 12 h. Dilution with HCl (2 mol
Experimental
For general experimental details see ref. 13. 1H n.m.r.
spectra were recorded at 400ꢀ13 MHz, and 13C n.m.r. spectra
at 100ꢀ62 MHz on a Bruker AM400 instrument operating
at 9ꢀ2 T. Multiplicities were determined from DEPT spectra.
D.s.c. measurements were carried out under nitrogen by using
a Polymer Laboratories PL DSC-12000 instrument with a
scanning rate of 10ꢁ/min. Samples which showed transitions
between ꢁ100 and +100ꢁC were scanned a second time to
eliminate thermal history. Data reported in Table 1 refer
to heating runs other than the ꢁrst. Identiꢁcation of the
particular liquid crystalline phases was performed by using
an Olympus BHSM-L-2 microscope equipped with a Linkam
THMS600 hot/cold stage and a Olympus long working distance
objective (magniꢁcation ꢂ20).
l
ꢂ1) followed by extraction with diethyl ether aꢃorded after
workup in the usual manner (9c) (7ꢀ12 g, 99%) as a clear oil.
ꢀmax 3333 (OH), 3012, 2926, 2855, 1514, 1464, 1417, 1335,
1017 cmꢂ1. ꢁH 0ꢀ88, t, J 6ꢀ5 Hz, 3H, (CH2)5CH3; 1ꢀ20–1ꢀ39,
m, 6H, (CH2)2(CH2)3CH3; 1ꢀ51–1ꢀ68, m, 2H, CH2CH2C4H9;
2ꢀ41, s, 1H, CH2OH; 2ꢀ58, br t, J 7ꢀ4 Hz, 2H, CH2C5H11
;
4ꢀ55, s, 2H, CH2OH; 7ꢀ13, br d, J 8ꢀ1 Hz, 2H, H 2 and
H 6; 7ꢀ22, br d, J 8ꢀ1 Hz, 2H, H 3 and H 5. ꢁC 14ꢀ02,
(CH2)5CH3; 22ꢀ54, (CH2)4CH2CH3; 28ꢀ92, (CH2)2CH2C3H7;
31ꢀ67, (CH2)3CH2C2H5; 35ꢀ59, CH2C5H11; 64ꢀ96, CH2OH;
127ꢀ02, 2C, C 3 and C 5; 128ꢀ45, 2C, C 2 and C 6; 138ꢀ06, C 1;
142ꢀ27, C 4.
General Procedure for Synthesis of the
Triphenylphosphonium Salts
1-Hexyl-4-iodomethylbenzene (10c)
A solution of triphenylphosphine (1ꢀ00 mol. equiv.) and the
alkyl or benzyl iodide (1ꢀ05 mol. equiv.) in anhydrous benzene
was heated to reꢂux for 24 h. In the cases where the product
was a solid the reaction mixture was ꢁltered and the white salt
washed several times with dry benzene. In the cases where
the product was an oil the reaction mixture was separated
in a separating funnel and the product washed several times
with dry benzene to give, after drying under vacuum, pure
RPPh3I [R = CH3 (93%), C3H7 (93%), C4H9 (91%), C5H11
(82%), C6H13 (98%), C7H15 (99%), CH2C6H4C2H5 (99%),
CH2C6H4C4H9 (99%), CH2C6H4C6H13 (98%)].
Chlorotrimethylsilane (8ꢀ01 g, 74ꢀ2 mmol) was added slowly
to a mixture of sodium iodide (16ꢀ7 g, 0ꢀ11 mol) and 4-
hexylbenzenemethanol (9c) (9ꢀ89 g, 44ꢀ5 mmol) in acetonitrile
(100 ml) cooled to 0ꢁC. After 1 h at 0ꢁC the reaction mix-
ture was allowed to warm to room temperature and was
stirred for 1 h after which time it was poured into water, and
extracted with diethyl ether. The combined organic extracts
were washed with water, saturated aqueous Na2S2O3, and
brine. Workup followed by ꢂash chromatography on silica
gel (hexanes/diethyl ether) aꢃorded (10c) (10ꢀ9 g, 97%) as a
clear oil which crystallized on standing to give white needles,
m.p. 34–36ꢁC. ꢀmax 3022, 2955, 2925, 2855, 1612, 1509, 1464,
1378, 1156, 830 cmꢂ1. ꢁH 0ꢀ88, t, J 6ꢀ7 Hz, 3H, (CH2)5CH3;
1ꢀ22–1ꢀ38, m, 6H, (CH2)2(CH2)3CH3; 1ꢀ50–1ꢀ68, m, 2H,
CH2CH2C4H9; 2ꢀ55, br t, J 7ꢀ4 Hz, 2H, CH2C5H11; 4ꢀ43, s,
2H, CH2I; 7ꢀ08, br d, J 8ꢀ1 Hz, 2H, H 3 and H 5; 7ꢀ27, br d, J
8ꢀ1 Hz, 2H, H 2 and H 6. ꢁC 6ꢀ19, CH2I; 14ꢀ07, (CH2)5CH3;
22ꢀ56, (CH2)4CH2CH3; 28ꢀ95, (CH2)2CH2C3H7; 31ꢀ22,
Hexyltriphenylphosphonium Iodide
Reaction of triphenylphosphine (25ꢀ0 g) and 1-iodohexane
(22ꢀ5 g) aꢃorded after workup C6H13PPh3+ Iꢂ (44ꢀ3 g, 98%)
as a viscous clear oil which on standing formed globular crys-
tals, m.p. 129–133ꢁC (Found: M+ꢃ ꢁ I, 347ꢀ1931. C24H28P+
requires m/z 347ꢀ1929). ꢀmax (CH2Cl2) 3066, 3038, 2958,
2862, 1589, 1486, 1467, 1439 (intense), 1402, 1338, 1114
CH2CH2C4H9; 31ꢀ67, (CH2)3CH2C2H5; 35ꢀ67, CH2C5H11
;
(intense), 997, 534, 508 cmꢂ1
(CH2)5CH3; 1ꢀ17–1ꢀ25, m, 4H, (CH2)3(CH2)2CH3; 1ꢀ53–
.
ꢁH 0ꢀ82, t, J 6ꢀ7 Hz, 3H,
128ꢀ60, 2C, C 3 and C 5; 128ꢀ81, 2C, C 2 and C 6; 136ꢀ36, C 4;
142ꢀ80, C 1. m/z 301 (M + ꢁ H, 1%), 246 (M ꢁ CH2=CHC2H5,
1), 231 (M ꢁ C5H11, 3), 175 (M ꢁ I, 100), 117 (8), 104 (32),
91 (21), 78 (10), 43 (16).
1ꢀ67, m, 4H, CH2(CH2)2C3H7; 3ꢀ50–3ꢀ71, m, 2H, CH2C5H11
;
7ꢀ67–7ꢀ85, m, 15H, CH (PPh3). ꢁC 13ꢀ77, (CH2)5CH3; 22ꢀ04,
(CH2)4CH2CH3; 22ꢀ38, d, J 7ꢀ0 Hz, CH2CH2C4H9; 22ꢀ93, d,
J 53ꢀ3 Hz, CH2C5H11; 29ꢀ94, d, J 15ꢀ5 Hz, (CH2)2CH2C3H7;
31ꢀ03, (CH2)3CH2C2H5; 117ꢀ88, d, J 85ꢀ9 Hz, 3C, (Cipso)3;
130ꢀ44, d, J 12ꢀ5 Hz, 6C, (Cmeta)6; 133ꢀ45, d, J 10ꢀ0 Hz, 6C,
4-Hexylbenzyltriphenylphosphonium Iodide (11c)
Reaction of triphenylphosphine (8ꢀ30 g, 31ꢀ2 mmol) with 1-
hexyl-4-iodomethylbenzene (10c) (10ꢀ6 g, 33ꢀ3 mmol) in reꢂux-
ing benzene (100 ml) for 3 h aꢃorded (11c) (17ꢀ9 g, 98%) as
white microcrystalline rods, m.p. 147–150ꢁC (Found: C, 65ꢀ9;
H, 6ꢀ0; I, 22ꢀ2. C31H34IP requires C, 66ꢀ0; H, 6ꢀ1; I, 22ꢀ5%.
(Cortho)6; 135ꢀ01, d, J 2ꢀ3 Hz, 3C, (Cpara)3. m/z (f.a.b.) 821
((C6H13PPh3)22+ Iꢂ, 2%), 681 (2), 363 (4), 347 (C6H13PPh3
100), 262 (+PPh3, 7), 183 (5).
,
+
Found: m/z, 437ꢀ2397.
C
31H34P requires m/z, 437ꢀ2398).
4-Hexylbenzaldehyde (8c)
ꢀmax (CH2Cl2) 3037, 2931, 2858, 1589, 1512, 1439 (intense),
1112 (intense), 998, 505 cmꢂ1
.
ꢁH 0ꢀ87, t, J 6ꢀ9 Hz, 3H,
A solution of 4-hexylbenzaldehyde diethyl acetal (10ꢀ0 g,
37ꢀ9 mmol) in dichloromethane (100 ml) was treated with dilute
HCl (3 drops, 2 mol lꢂ1) and water (1ꢀ4 ml, 75ꢀ8 mmol) at
room temperature. After 2ꢀ5 h the reaction mixture was diluted
with water and extracted with dichloromethane. Workup in
the usual manner aꢃorded (8c) (7ꢀ12 g, 99%) as a clear oil.
ꢀmax 2928, 2857, 2731, 1694 (C=O), 1606, 1575, 1466, 1386,
(CH2)5CH3; 1ꢀ20–1ꢀ35, m, 6H, (CH2)2(CH2)3CH3; 1ꢀ47–
1ꢀ56, m, 2H, CH2CH2C4H9; 2ꢀ51, br td, J 7ꢀ8, 1ꢀ5 Hz, 2H,
CH2C5H11; 5ꢀ12, d, J 13ꢀ9 Hz, 2H, CH2PPh3; 6ꢀ92–6ꢀ98, m,
4H, C6H13C6H4CH2PPh3; 7ꢀ60–7ꢀ70, m, 12H, (Hmeta
) and
6
(Hortho)6, PPh3; 7ꢀ79, br tq, J 6ꢀ9, 1ꢀ9 Hz, 3H, (Hpara)3,
PPh3. ꢁC 13ꢀ63, (CH2)5CH3; 22ꢀ09, (CH2)4CH2CH3; 28ꢀ29,
(CH2)2CH2C3H7; 30ꢀ38, d, J 47ꢀ5 Hz, CH2PPh3; 30ꢀ69,
1305, 1168 cmꢂ1
.
ꢁH 0ꢀ88, br t, J 6ꢀ4 Hz, 3H, C5H10CH3;
CH2CH2C4H9; 31ꢀ12, (CH2)3CH2C2H5; 34ꢀ97, CH2C5H11
;
1ꢀ21–1ꢀ39, m, 6H, (CH2)2(CH2)3CH3; 1ꢀ57–1ꢀ69, m, 2H,
CH2CH2C4H9; 2ꢀ67, br t, J 7ꢀ4 Hz, 2H, CH2C5H11; 7ꢀ32,
br d, J 8ꢀ0 Hz, 2H, H 3 and H 5; 7ꢀ79, br d, J 8ꢀ1 Hz, 2H,
H 2 and H 6; 9ꢀ96, s, 1H, CH=O. ꢁC 13ꢀ95, (CH2)5CH3;
116ꢀ98, d, J 85ꢀ7 Hz, 3C, (Cipso)3; 123ꢀ14, d, J 8ꢀ6 Hz,
C 1; 128ꢀ50, d, 2ꢀ8 Hz, 2C, C 2 and C 6; 129ꢀ83, d,
12ꢀ5 Hz, 6C, (Cmeta)6; 130ꢀ74, d, 5ꢀ3 Hz, 2C, C 3
J
J
J

Stilbene Derivatives
431
and C 5; 134ꢀ85, d, J 9ꢀ7 Hz, 6C, (Cortho)6; 134ꢀ76, d,
(f.a.b.) 1001 ((C6H13C6H4CH2PPh3)22+ Iꢂ, 1%), 588 (2), 437
(C6H13C6H4CH2PPh3+, 100), 379 (4), 307 (9), 289 (5), 262
(+PPh3, 10), 175 (9), 154 (22).
give in order of increasing polarity: (i) a mixture (90 : 10) of
J
2ꢀ5 Hz, 3C, (Cpara)3; 143ꢀ07, d, J 4ꢀ1 Hz, C 4. m/z
(E)- and (Z)-1-(3-bromophenyl)oct-1-ene (5g) (0ꢀ18 g, 5%) as
a clear oil, Kugelrohr 140–155ꢁC/0ꢀ05 mmHg (Found: M+ꢃ
,
266ꢀ0668.
C
14H1979Br requires M+ꢃ
,
266ꢀ0670. Found:
M+ꢃ, 268ꢀ0650. C14H1981Br requires M+ꢃ, 268ꢀ0650). ꢀmax
2956, 2926, 2854, 1592, 1561, 1469, 1422, 1384 cmꢂ1
. m/z
266/268 (M+, 25/24%), 195/197 (M ꢁ C5H11, 14/13), 182/184
3,5-Dibromobenzaldehyde (1f)
(M ꢁ CH2=CHC4H9, 80/79), 169 (10), 129 (14), 116 (100),
A suspension of 1,3,5-tribromobenzene (1a) (10ꢀ0 g, 31ꢀ7
mmol) in diethyl ether (250 ml) at ꢁ78ꢁC was treated drop-
wise with butyllithium (13ꢀ3 ml, 33ꢀ3 mmol). After 45 min
dimethylformamide (6ꢀ95 g, 95ꢀ2 mmol) was added to the
mixture, which was then stirred for a further 1 h. Dilution
with HCl (100 ml, 2 mol lꢂ1) followed by workup in the usual
manner aꢃorded a cream-coloured solid which was puriꢁed by
ꢂash chromatography on silica gel (hexanes/diethyl ether) to
give (1f) (7ꢀ92 g, 95%) as a white solid which crystallized from
diethyl ether/hexanes as needles, m.p. 89–92ꢁC. ꢀmax 3076,
2836, 1707 (C=O), 1561, 1432 cmꢂ1. ꢁH 7ꢀ94, br d, J 1ꢀ7 Hz,
2H, H 2 and H 6; 7ꢀ92, br d, J 1ꢀ7 Hz, 1H, H 4; 9ꢀ91, s, 1H,
CH=O. ꢁC 123ꢀ89, 2C, C 3 and C 5; 131ꢀ15, 2C, C 2 and C 6;
138ꢀ84, C 1; 139ꢀ51, C 4; 189ꢀ10, CH=O.
115 (51), 103 (10), 91 (12), 77 (10), 55 (25), 43 (28).
E
Isomer: ꢁH 0ꢀ92, t, J 6ꢀ9 Hz, 3H, (CH2)5CH3; 1ꢀ25–1ꢀ38,
m, 6H, (CH2)2(CH2)3CH3; 1ꢀ44–1ꢀ50, m, 2H, CH2CH2C4H9;
2ꢀ20, qd,
J
6ꢀ8 Hz, 2H, CH2C5H11
;
6ꢀ18–6ꢀ35, m, 2H,
CH=CHC6H13; 7ꢀ14, t, J 7ꢀ8 Hz, 1H, H 5; 7ꢀ24, dt, J 7ꢀ9,
1ꢀ1 Hz, 1H, H 6; 7ꢀ30, ddd, J 7ꢀ9, 1ꢀ9, 1ꢀ2 Hz, 1H, H 4; 7ꢀ48, t, J
1ꢀ7 Hz, 1H, H 2. ꢁC 14ꢀ07, (CH2)5CH3; 22ꢀ60, (CH2)4CH2CH3;
28ꢀ88, (CH2)2CH2C4H9; 29ꢀ17, (CH2)3CH2C2H5; 31ꢀ71,
CH2CH2C4H9; 32ꢀ98, CH2C5H11; 122ꢀ68, C 3; 124ꢀ53, C 6;
128ꢀ34, CH=CHC6H13; 128ꢀ73, C 2; 129ꢀ53, C 5; 129ꢀ88, C 4;
132ꢀ86, CH=CHC6H13; 140ꢀ11, C 1; and (ii) a mixture (95 : 5) of
(E)- and (Z)-3-bromo-5-(oct-1-enyl)benzaldehyde (5h) (3ꢀ46 g,
89%) as a clear oil, Kugelrohr 110–120ꢁC/0ꢀ05 mmHg (Found:
C, 60ꢀ8; H, 6ꢀ5; Br, 27ꢀ3. C15H19BrO requires: C, 61ꢀ0; H, 6ꢀ5;
Br, 27ꢀ1%. Found: M+ꢃ, 294ꢀ0612. C15H1979BrO requires
M+ꢃ, 294ꢀ0619. Found: M+ꢃ, 296ꢀ0598. C15H1981BrOrequires
M+ꢃ, 296ꢀ0599). ꢀmax 2926, 2855, 2721, 1704 (C=O), 1591,
1564, 1450, 1378 cmꢂ1. ꢁH 0ꢀ92, t, J 6ꢀ9 Hz, 3H, (CH2)5CH3;
1ꢀ25–1ꢀ39, m, 6H, (CH2)2(CH2)3CH3; 1ꢀ44–1ꢀ53, m, 2H,
CH2CH2C4H9; 2ꢀ26, tq, J 7ꢀ7, 1ꢀ5 Hz, 2H, CH2C5H11; 6ꢀ37–
6ꢀ48, m, 2H, CH=CHC6H13; 7ꢀ73, br t, J 1ꢀ7 Hz, 1H, H 4;
7ꢀ76 and 7ꢀ83, br t, J 1ꢀ7 Hz, 1H each, H 2 and H 6; 9ꢀ96,
s, 1H, CH=O. ꢁC 14ꢀ05, (CH2)5CH3; 22ꢀ54, (CH2)4CH2CH3;
28ꢀ85, (CH2)2CH2C3H7; 28ꢀ99, (CH2)3CH2C2H5; 31ꢀ65,
CH2CH2C4H9; 32ꢀ97, CH2C5H11; 123ꢀ40, C 3; 125ꢀ60, C 6;
(E)- and (Z)-1-(3,5-Dibromophenyl)oct-1-ene (1m)
A solution of heptyltriphenylphosphonium iodide (24ꢀ4 g,
50ꢀ0 mmol) in tetrahydrofuran (100 ml) was treated drop-
wise with butyllithium (21ꢀ0 ml, 50ꢀ0 mmol) at 0ꢁC. After
15 min the reaction temperature was raised to 25ꢁC during
which time a dark red colour formed. The mixture was
stirred for 3 h and a solution of 3,5-dibromobenzaldehyde
(1f) (6ꢀ00 g, 22ꢀ7 mmol) in tetrahydrofuran (15 ml) was then
added. After heating of the mixture under reꢂux for 12 h
the solvents were removed under vacuum and the residue
was extracted with dichloromethane. The combined organic
fractions were washed with brine, dried (MgSO4) and concen-
trated to yield a red oily residue which was extracted (Soxhlet)
with hexanes. The resultant yellow oil was puriꢁed by ꢂash
chromatography on silica gel (hexanes) to give a mixture (95 : 5)
of (E)- and (Z)-1-(3,5-dibromophenyl)oct-1-ene (1m) (7ꢀ43 g,
95%) as a pale yellow oil, Kugelrohr 115–125ꢁC/0ꢀ7 mmHg
127ꢀ20, CH=CHC6H13
CH=CHC6H13
;
130ꢀ25, C 2; 134ꢀ24, C 4; 134ꢀ96,
;
138ꢀ01, C 1; 140ꢀ93, C 5; 190ꢀ78, CH=O.
m/z 296/294 (M+, 20/19%), 210/212 (M ꢁ CH2=CHC4H9,
100/98), 197(10), 145 (8), 128 (18), 116 (95), 102 (10), 89 (8),
77 (10), 63 (10), 55 (21), 43 (40), 41 (32).
Use of a mixture (36 : 64) of (E)- and (Z)-1-(3,5-dibromo-
phenyl)oct-1-ene (1m) (3ꢀ56 g, 10ꢀ3 mmol) gave in order
of increasing polarity: (i) a mixture (35 : 65) of (E)- and
(Z)-1-(3-bromophenyl)oct-1-ene (5g) (0ꢀ10 g, 4%) as a clear
(Found: C, 48ꢀ8; H, 5ꢀ3.
C
14H18Br2 requires C, 48ꢀ6;
H, 5ꢀ2%. Found: M+ꢃ, 343ꢀ9776. C14H1879Br2 requires
M+ꢃ, 343ꢀ9734. Found: M+ꢃ, 345ꢀ9753. C14H1879Br81Br
requires M+ꢃ, 345ꢀ9755. Found: M+ꢃ, 347ꢀ9733. C14H1881Br2
requires M+ꢃ, 347ꢀ9734). ꢀmax 3012, 2956, 2925, 2855, 1650,
oil (Found: M+ꢃ
,
266ꢀ0668. C14H1979Br requires M+ꢃ
,
,
266ꢀ0670. Found: M+ꢃ, 268ꢀ0650. C14H1981Br requires M+ꢃ
268ꢀ0650). ꢀmax 2956, 2926, 2855, 1592, 1556 cmꢂ1
. m/z
266/268 (M+, 21/20%), 195/197 (M ꢁ C5H11, 10/10), 182/184
(M ꢁ CH=CHC4H9, 10/10), 169 (10), 129 (11), 116 (100), 115
(52), 103 (10), 91 (12), 77 (12), 55 (23), 43 (30). Z Isomer:
ꢁH 0ꢀ88, t, J 7ꢀ1 Hz, 3H, (CH2)5CH3; 1ꢀ25–1ꢀ38, m, 6H,
(CH2)2(CH2)3CH3; 1ꢀ44–1ꢀ50, m, 2H, CH2CH2C4H9; 2ꢀ28,
qd, J 7ꢀ4, 1ꢀ8 Hz, 2H, CH2C5H11; 5ꢀ71, dt, J 11ꢀ7, 7ꢀ3 Hz,
1H, CH=CHC6H13; 6ꢀ18–6ꢀ35, m, 1H, CH=CHC6H13; 7ꢀ17–
7ꢀ22, m, 2H, H 4 and H 5; 7ꢀ32–7ꢀ37, m, 1H, H 6; 7ꢀ41, br s,
1H, H 2. ꢁC 14ꢀ06, (CH2)5CH3; 22ꢀ62, (CH2)4CH2CH3;
28ꢀ55, (CH2)2CH2C3H7; 28ꢀ96, (CH2)3CH2C2H5; 29ꢀ79,
CH2CH2C4H9; 31ꢀ70, CH2C5H11; 122ꢀ22, C 3; 127ꢀ29, C 6;
127ꢀ35, CH=CHC6H13; 129ꢀ35, C 2; 129ꢀ92, C 5; 131ꢀ56, C 4;
134ꢀ67, CH=CHC6H13; 139ꢀ90, C 1; and (ii) a mixture (36 : 64)
of (E)- and (Z)-3-bromo-5-(oct-1-enyl)benzaldehyde (5h) (2ꢀ72 g,
90%) as a clear oil, Kugelrohr 110–120ꢁC/(0ꢀ05 mmHg) (Found:
C, 60ꢀ8; H, 6ꢀ5; Br, 27ꢀ3. C15H19BrO requires C, 61ꢀ0; H, 6ꢀ5;
Br, 27ꢀ1%. Found: M+ꢃ, 294ꢀ0612. C15H1979BrO requires
1581, 1544, 1465, 1412, 1386 cmꢂ1
.
m/z 344/346/348 (M+,
12/28/12%), 260/262/264 (M ꢁ CH2=CHC4H9, 50/100/50),
194/196 (M ꢁ Br ꢁ C5H11, 25/24), 182/184 (14/13), 128 (20),
115 (194/196 ꢁ Br, 82), 102 (18), 55 (12), 43 (32). E Isomer:
ꢁH 0ꢀ89, br t, J 6ꢀ8 Hz, 3H, (CH2)5CH3; 1ꢀ27–1ꢀ39, m, 6H,
(CH2)2(CH2)3CH3; 1ꢀ41–1ꢀ52, m, 2H, CH2CH2C4H9; 2ꢀ23,
td, J 7ꢀ1, 5ꢀ5 Hz, 2H, CH=CHCH2C5H11; 6ꢀ22–6ꢀ33, m, 2H,
CH=CHC6H13; 7ꢀ39, d, J 1ꢀ7 Hz, 2H, H 2 and H 6; 7ꢀ46, t, J
1ꢀ7 Hz, 1H, H 4. ꢁC 14ꢀ08, (CH2)5CH3; 22ꢀ59, (CH2)4CH2CH3;
28ꢀ85, (CH2)2CH2C3H7; 29ꢀ04, (CH2)3CH2C2H5; 31ꢀ38,
CH2CH2C4H9; 32ꢀ95, CH2C5H11; 122ꢀ98, 2C, C 3 and C 5;
127ꢀ16, CH=CHC6H13; 127ꢀ61, 2C, C 2 and C 6; 131ꢀ87, C 4;
134ꢀ62, CH=CHC6H13; 141ꢀ60, C 1.
(E)- and (Z)-3-Bromo-5-(oct-1-enyl)benzaldehyde (5h)
A solution of a mixture (95 : 5) of (E)- and (Z)-1-(3,5-
dibromophenyl)oct-1-ene (1m) (4ꢀ56 g, 13ꢀ2 mmol) in diethyl
ether (100 ml) at ꢁ78ꢁC was treated dropwise with butyl-
lithium (5ꢀ80 ml, 14ꢀ5 mmol). After 1ꢀ5 h dimethylformamide
(3ꢀ21 ml, 39ꢀ5 mmol) was injected into the reaction mixture
which was then stirred for a further 1ꢀ5 h at ꢁ78ꢁC. Quench-
ing with HCl (20 ml, 2 mol lꢂ1) followed by workup in the
usual manner aꢃorded a brown oil which was puriꢁed by
ꢂash chromatography on silica gel (hexanes/diethyl ether) to
M+ꢃ
,
294ꢀ0619. Found: M+ꢃ
,
296ꢀ0598. C15H1981BrO
requires M+ꢃ, 296ꢀ0599). ꢀmax 2926, 2855, 2721, 1704 (C=O),
1591, 1564, 1450, 1378 cmꢂ1
.
m/z 296/294 (M+, 20/19%),
210/212 (M ꢁ CH2=CHC4H9, 100/98), 197 (10), 145 (8), 128
(18), 116 (95), 102 (10), 89 (8), 77 (10), 63 (10), 55 (21), 43 (40),
41 (32). Z Isomer: ꢁH 0ꢀ91, t, J 7ꢀ1 Hz, 3H, (CH2)5CH3;
1ꢀ26–1ꢀ39, m, 6H, (CH2)2(CH2)3CH3; 1ꢀ43–1ꢀ54, m, 2H,
CH2CH2C4H9; 2ꢀ32, qd, J 7ꢀ3, 1ꢀ8 Hz, 2H, CH2C5H11
;

432
G. M. Day et al.
5ꢀ84, dt, J 11ꢀ6, 7ꢀ4 Hz, 1H, CH=CHC6H13
;
6ꢀ34–6ꢀ50,
230 (27), 215 (20), 174 (10), 160 (100), 145 (15), 129 (27), 117
(32), 95 (20), 69 (20), 55 (32), 43 (42).
m, 1H, CH=CHC6H13; 7ꢀ66, br t, J 1ꢀ7 Hz, 1H, H 4; 7ꢀ70
and 7ꢀ88, br t, J 1ꢀ7 Hz, 1H each, H 2 and H 6; 9ꢀ97, s,
1H, CH=O. ꢁC 14ꢀ01, (CH2)5CH3; 22ꢀ54, (CH2)4CH2CH3;
28ꢀ49, (CH2)2CH2C3H7; 28ꢀ85, (CH2)3CH2C2H5; 29ꢀ59,
CH2CH2C4H9; 31ꢀ60, CH2C5H11; 123ꢀ01, C 3; 126ꢀ14, C 6;
1-[3,5-Bis(oct-1-enyl)phenyl]-2-(4-ethylphenyl)ethene (12)
A suspension of 4-ethylbenzyltriphenylphosphonium iodide
(3ꢀ89 g, 7ꢀ66 mmol) in tetrahydrofuran (70 ml) was treated
dropwise with butyllithium (3ꢀ06 ml, 7ꢀ66 mmol) at 0ꢁC. After
5 min the deep red mixture was allowed to warm to room
temperature and was treated with a solution of a mixture of
stereoisomers of 3,5-bis(oct-1-enyl)benzaldehyde (6f) (1ꢀ10 g,
3ꢀ48 mmol) in tetrahydrofuran (10 ml). The reaction mixture
was heated under reꢂux for 2 h after which time it was con-
centrated under vacuum and extracted with dichloromethane.
The combined organic fractions were washed with brine, dried
(MgSO4) and concentrated to yield a red oily residue which
was extracted (Soxhlet) with hexanes. The resultant yellow oil
was puriꢁed by ꢂash chromatography on silica gel (hexanes) to
give a mixture of isomers of the ethene (12) (1ꢀ31 g, 88%) as a
pale yellow oil. A portion (0ꢀ10 g) was puriꢁed further by p.l.c.
on silica gel to give the title compound (mixture of isomers)
(89 mg, 89%) as a clear oil, Kugelrohr 200–225ꢁC/0ꢀ8 mmHg
(Found: C, 89ꢀ6; H, 10ꢀ2. C32H44 requires C, 89ꢀ7; H, 10ꢀ4%.
Found: M+ꢃ, 428ꢀ3439. C32H44 requires M+ꢃ, 428ꢀ3443).
m/z 428 (M+, 100%), 413 (M ꢁ CH3, 2), 386 (2), 371 (3), 357
(2), 259 (7), 119 (20), 91 (8), 55 (7), 43 (15). ꢀmax 3007, 2958,
128ꢀ58, CH=CHC6H13
;
130ꢀ04, C 2; 136ꢀ29, C 4; 137ꢀ08,
CH=CHC6H13; 137ꢀ73, C 1; 140ꢀ63, C 5; 190ꢀ72, CH=O.
1-Bromo-3,5-bis(oct-1-enyl)benzene (5k)
A solution of heptyltriphenylphosphonium iodide (10ꢀ7 g,
22ꢀ0 mmol) in tetrahydrofuran (50 ml) was treated dropwise
with butyllithium (8ꢀ80 ml, 22ꢀ0 mmol) at 0ꢁC. After 15 min
the reaction mixture was allowed to warm to room temperature
during which time a dark red colour formed. The mixture was
stirred for 3 h and was then treated with a solution of a mixture
(85 : 15) of (E)- and (Z)-3-bromo-5-(oct-1-enyl)benzaldehyde
(5h) (2ꢀ95 g, 10ꢀ0 mmol) in tetrahydrofuran (10 ml). After
heating under reꢂux for 12 h the solvents were removed under
vacuum and the residue was extracted with dichloromethane.
The combined organic fractions were washed with brine, dried
(MgSO4) and concentrated to yield a red oily residue which
was extracted (Soxhlet) with hexanes. The resultant yellow
oil was puriꢁed further by ꢂash chromatography on silica
gel (hexanes) to give a mixture of three isomers of 1-bromo-
3,5-bis(oct-1-enyl)benzene (5k) (3ꢀ61 g, 96%) as a pale yellow
oil, Kugelrohr 140–150ꢁC/0ꢀ04 mmHg (Found: C, 70ꢀ0; H,
2926, 2854, 1585, 1511, 1458, 1385 cmꢂ1
.
Reduction of 3,5-Bis(oct-1-enyl)benzaldehyde (6f) with
Pd–C/H2
8ꢀ9.
C
22H33Br requires C, 70ꢀ0; H, 8ꢀ9%. Found: M+ꢃ
,
376ꢀ1766.
C
22H3379Br requires M+ꢃ
,
376ꢀ1766. Found:
M+ꢃ, 378ꢀ1746. C22H3381Br requires M+ꢃ, 378ꢀ1745). m/z
376/378 (M+, 88/90%), 319/321 (M ꢁ C4H9, 8/7), 292/294
(M ꢁ CH2=CHC4H9, 14/13), 280/282 (14/14), 240 (5), 226
(50), 210 (30), 155 (100), 142 (57), 129 (57), 115 (37), 111
(18), 97 (10), 69 (48), 55 (50), 43 (62). ꢀmax 3010, 2956, 2926,
A solution of the aldehyde (6f) (0ꢀ11 g, 0ꢀ34 mmol) in
ethanol (10 ml) was stirred with palladium on carbon (10%,
18 mg, 16ꢀ9 ꢂmol) under a hydrogen atmosphere for 45 min.
The reaction mixture was then ꢁltered through Celite and
concentrated under vacuum to give a clear oil which was
puriꢁed by ꢂash chromatography on silica gel (hexanes/diethyl
ether) to give in order of increasing polarity: (i) 1-methyl-
3,5-dioctylbenzene (7g) as a clear oil (8 mg, 7%), Kugelrohr
150–155ꢁC/0ꢀ1 mmHg (Found: C, 87ꢀ2; H, 12ꢀ9. C23H40
requires C, 87ꢀ3; H, 12ꢀ7%. Found: M+ꢃ, 316ꢀ3123. C23H40
requires M+ꢃ, 316ꢀ3130). ꢀmax 3012, 2926, 2855, 1604, 1459,
2855, 1591, 1557, 1466, 1378 cmꢂ1
.
3,5-Bis(oct-1-enyl)benzaldehyde (6f)
A solution of a mixture of three stereoisomers of 1-bromo-3,5-
bis(oct-1-enyl)benzene (5k) (1ꢀ65 g, 4ꢀ38 mmol) in tetrahydro-
furan (20 ml) at ꢁ78ꢁC was treated dropwise with butyllithium
(1ꢀ93 ml, 4ꢀ81 mmol), forming a deep red-brown solution. After
1ꢀ5 h dimethylformamide (1ꢀ15 ml, 1ꢀ31 mmol) was injected
into the reaction mixture which was then stirred for a fur-
1384 cmꢂ1
.
ꢁH 0ꢀ88, t, J 7ꢀ0 Hz, 6H, 3-(CH2)7CH3 and
5-(CH2)7CH3; 1ꢀ20–1ꢀ38, m, 20H, 3-(CH2)2(CH2)5CH3 and
5-(CH2)2(CH2)5CH3; 1ꢀ54–1ꢀ63, m, 4H, 3-CH2CH2C6H13 and
5-CH2CH2C6H13; 2ꢀ29, s, 3H, 1-CH3; 2ꢀ53, br t, J 7ꢀ6 Hz,
4H, 3-CH2C7H15 and 5-CH2C7H15; 6ꢀ79, br s, 1H, H 4; 6ꢀ81,
br s, 2H, H 2 and H 6. ꢁC 14ꢀ10, 2C, 3-(CH2)7CH3 and
5-(CH2)7CH3; 21ꢀ33, 1-CH3; 22ꢀ68, 2C, 3-(CH2)6CH2CH3
and 5-(CH2)6CH2CH3; 29ꢀ28, 2C, 3-(CH2)4CH2C3H7 and
5-(CH2)4CH2C3H7; 29ꢀ49, 4C, 3-(CH2)2CH2CH2C4H9 and
5-(CH2)2CH2CH2C4H9; 31ꢀ62, 2C, 3-CH2CH2C6H13 and
ther 1ꢀ5 h at ꢁ78ꢁC. Quenching with HCl (5 ml, 2 mol lꢂ1
)
followed by workup and ꢂash chromatography on silica gel
(hexanes/diethyl ether) gave in order of increasing polarity: (i)
a mixture of stereoisomers of 1,3-bis(oct-1-enyl)benzene (6e)
(72 mg, 5%) as a clear oil, Kugelrohr 140–150ꢁC/0ꢀ05 mmHg
(Found: M+ꢃ, 298ꢀ2663. C22H34 requires M+ꢃ, 298ꢀ2661).
ꢀmax 2927, 2857, 2855, 1457, 1384, 909 cmꢂ1. m/z 298 (M+,
74%), 283 (M ꢁ CH3, 4), 255 (M ꢁ C3H7, 4), 241 (M ꢁ C4H9,
9), 227 (M ꢁ C5H11, 20), 214 (M ꢁ CH2=CHC4H9, 18), 202
(11), 155 (10), 143 (32), 129 (100), 117 (30), 111 (20), 105 (10),
91 (18), 69 (45), 55 (40), 43 (52); (ii) a mixture of stereoisomers
of 3,5-bis(oct-1-enyl)benzaldehyde (6f) (1ꢀ30 g, 92%) as a clear
oil, Kugelrohr 165–175ꢁC/0ꢀ1 mmHg (Found: C, 84ꢀ6; H,
5-CH2CH2C6H13
;
31ꢀ91, 2C, 3-(CH2)5CH2C2H5 and 5-
(CH2)5CH2C2H5; 35ꢀ92, 2C, 3-CH2C7H15 and 5-CH2C7H15
;
125ꢀ59, C 4; 126ꢀ47, 2C, C 2 and C 6; 137ꢀ52, C 1; 142ꢀ80,
2C, C 3 and C 5. m/z 316 (M+, 52%), 301 (M ꢁ CH3, 3),
273 (M ꢁ C3H7, 8), 259 (M ꢁ C4H9, 10), 245 (M ꢁ C5H11
,
4), 231 (M ꢁ C6H13, 9), 218 (M ꢁ CH2=CHC5H11, 100), 203
(218 ꢁ CH3, 10), 175 (218 ꢁ C3H7, 2), 161 (218 ꢁ C4H9, 8), 147
10ꢀ4.
C
23H34O requires C, 84ꢀ6; H, 10ꢀ5%. Found: M+ꢃ
,
(218 ꢁ C5H11, 8), 133 (218 ꢁ C6H13, 10), 119 (218 ꢁ C7H15
,
23H34O requires M+ꢃ, 326ꢀ2610). ꢀmax 3010,
96), 105 (218 ꢁ C8H17, 50), 91 (18), 71 (C5H11+, 10), 57
(C4H9+, 18), 43 (C3H7+, 30); (ii) 3,5-dioctylbenzaldehyde (7i)
as a clear oil (26 mg, 23%), Kugelrohr 160–165ꢁC/0ꢀ05 mmHg
326ꢀ2610.
C
2926, 2855, 2719, 1703 (C=O), 1593, 1462, 1379 cmꢂ1. m/z
326 (M+, 100%), 287 (10), 269 (5), 255 (M ꢁ C5H11, 10), 242
(M ꢁ CH2=CHC4H9, 18), 230 (10), 158 (40), 143 (30), 129
(78), 117 (18), 91 (12), 69 (22), 55 (28), 43 (40); and (iii) a
clear oil (50 mg) consisting of several components of which only
the mixture of stereoisomers of 3,5-bis(oct-1-enyl)benzoic acid
(6g) could be identiꢁed (Found: M+ꢃ, 342ꢀ2553. C23H34O2
requires M+ꢃ, 342ꢀ2559). ꢀmax 3440 (OH), 2926, 2855, 1699
(Found: C, 83ꢀ3; H, 11ꢀ6.
C
23H38O requires C, 83ꢀ6; H,
11ꢀ6%. Found: M+ꢃ, 330ꢀ2914. C23H38O requires M+ꢃ
,
330ꢀ2923). ꢀmax 2926, 2855, 2717, 1703 (C=O), 1602, 1461,
1385 cmꢂ1
.
ꢁH 0ꢀ88, t, J 7ꢀ0 Hz, 6H, 3-(CH2)7CH3 and
5-(CH2)7CH3; 1ꢀ21–1ꢀ39, m, 20H, 3-(CH2)2(CH2)5CH3 and
5-(CH2)2(CH2)5CH3; 1ꢀ58–1ꢀ69, m, 4H, 3-CH2CH2C6H13 and
5-CH2CH2C6H13; 2ꢀ65, br t, J 7ꢀ5 Hz, 4H, 3-CH2C7H15 and
5-CH2C7H15; 7ꢀ26, br d, J 1ꢀ6 Hz, 1H, H 4; 7ꢀ51, br d, J
(C=O), 1598, 1456, 1384, 1143 cmꢂ1
.
m/z 342 (M+, 28%),
313 (M ꢁ C2H5, 10), 295 (313 ꢁ H2O, 5), 257 (20), 245 (42),

Stilbene Derivatives
433
1ꢀ5 Hz, 2H, H 2 and H 6; 9ꢀ97, s, 1H, 1-C(O)H. ꢁC 14ꢀ06, 2C,
3-(CH2)7CH3 and 5-(CH2)7CH3; 22ꢀ63, 2C, 3-(CH2)6CH2CH3
and 5-(CH2)6CH2CH3; 29ꢀ22, 2C, 3-(CH2)4CH2C3H7 and
5-(CH2)4CH2C3H7; 29ꢀ40, 4C, 3-(CH2)2(CH2)2C4H9 and
5-(CH2)2(CH2)2C4H9; 31ꢀ29, 2C, 3-CH2CH2C6H13 and 5-
CH2CH2C6H13; 31ꢀ84, 2C, 3-(CH2)5CH2C2H5 and 5-(CH2)5-
CH2C2H5; 35ꢀ59, 2C, 3-CH2C7H15 and 5-CH2C7H15; 127ꢀ13,
2C, C 2 and C 6; 135ꢀ01, C 4; 136ꢀ61, C 1; 143ꢀ81, 2C, C 3 and
C 5; 192ꢀ88, C(O)H. m/z 330 (M+, 79%), 232 (100), 220 (10),
217 (22), 204 (12), 133 (28), 117 (12), 105 (78), 91 (32), 79 (10),
71 (C5H11+, 14), 57 (C4H9+, 37), 43 (C3H7+, 52); and (iii) 3,5-
dioctylbenzenemethanol (7h) a clear oil (80 mg, 70%), Kugelrohr
400-(CH2)2(CH2)5CH3; 1ꢀ46–1ꢀ53, m, 4H, 30-CH2CH2C4H9
and 50-CH2CH2C4H9; 1ꢀ56–1ꢀ61, m, 2H, 400-CH2CH2C6H13
2ꢀ46, br t, J 7ꢀ9 Hz, 4H, 30-CH2C5H11 and 50-CH2C5H11
;
;
2ꢀ55, br t, J 7ꢀ9 Hz, 2H, 400-CH2C7H15; 6ꢀ51, br s, 2H, H 1
and H 2; 6ꢀ81, br s, 1H, H 40; 6ꢀ90, d, J 1ꢀ4 Hz, 2H, H 20 and
H 60; 7ꢀ01, d, J 8ꢀ0 Hz, 2H, H 200 and H 600; 7ꢀ17, br d, J
8ꢀ0 Hz, 2H, H 300 and H 500. ꢁC 14ꢀ11, 3C, 30-(CH2)5CH3, 50-
(CH2)5CH3 and 400-(CH2)7CH3; 22ꢀ61, 2C, 30-(CH2)4CH2CH3
and 50-(CH2)4CH2CH3; 22ꢀ67, 400-(CH2)6CH2CH3; 28ꢀ99,
2C, 30-(CH2)2CH2C3H7 and 50-(CH2)2CH2C3H7; 29ꢀ28, 400-
(CH2)4CH2C3H7; 29ꢀ35, 400-(CH2)3CH2C4H7; 29ꢀ49, 400-
(CH2)2CH2C5H11
;
31ꢀ38, 2C, 30-CH2CH2C4H9 and 50-
165–170ꢁC/0ꢀ1 mmHg (Found: C, 83ꢀ2; H, 12ꢀ4. C23H40
O
O
CH2CH2C4H9; 31ꢀ44, 400-CH2CH2C6H13
;
31ꢀ76, 2C, 30-
requires C, 83ꢀ1; H, 12ꢀ1%. Found: M+ꢃ, 332ꢀ3075. C23H40
(CH2)3CH2C2H5 and 50-(CH2)3CH2C2H5; 31ꢀ90, 400-(CH2)5-
CH2C2H5; 35ꢀ72, 2C, 30-CH2C5H11 and 50-CH2C5H11; 35ꢀ84,
400-CH2C7H15; 126ꢀ21, 2C, C 20 and C 60; 127ꢀ45, C 40; 128ꢀ09,
2C, C 200 and C 600; 128ꢀ78, C 300 and C 500; 129ꢀ71, C 2; 130ꢀ00,
C 1; 134ꢀ74, C 100; 137ꢀ17, C 10; 141ꢀ80, C 400; 142ꢀ60, 2C,
C 30 and C 50. m/z 460 (M+, 100%), 416 (M ꢁ C3H8, 2), 390
(M ꢁ CH2=CHC3H7, 10), 361 (M ꢁ C7H15, 4), 319 (4), 277
(8), 207 (9), 179 (4), 129 (4), 105 (8), 57 (C4H9+, 9), 43
(C3H7+, 18).
requires M+ꢃ, 332ꢀ3079). ꢀmax 3333 (OH), 2926, 2854, 1604,
1456, 1384 cmꢂ1. ꢁH 0ꢀ88, t, J 7ꢀ1 Hz, 6H, 3-(CH2)7CH3 and
5-(CH2)7CH3; 1ꢀ21–1ꢀ37, m, 20H, 3-(CH2)2(CH2)5CH3 and
5-(CH2)2(CH2)5CH3; 1ꢀ58–1ꢀ65, m, 4H, 3-CH2CH2C6H13 and
5-CH2CH2C6H13; 1ꢀ77, s, 1H, 1-CH2OH; 2ꢀ58, br t, J 8ꢀ0 Hz,
4H, 3-CH2C7H15 and 5-CH2C7H15; 4ꢀ65, br s, 2H, 1-CH2OH;
6ꢀ93, br s, 1H, H 4; 7ꢀ00, br s, 2H, H 2 and H 6. ꢁC 14ꢀ09, 2C,
3-(CH2)7CH3 and 5-(CH2)7CH3; 22ꢀ66, 2C, 3-(CH2)6CH2CH3
and 5-(CH2)6CH2CH3; 29ꢀ26, 2C, 3-(CH2)4CH2C3H7 and
5-(CH2)4CH2C3H7; 29ꢀ43, 4C, 3-(CH2)2(CH2)2C4H9 and
5-(CH2)2(CH2)2C4H9; 31ꢀ55, 2C, 3-CH2CH2C6H13 and 5-
CH2CH2C6H13; 31ꢀ89, 2C, 3-(CH2)5CH2C2H5 and (CH2)5-
CH2C2H5; 35ꢀ92, 2C, 3-CH2C7H15 and 5-CH2C7H15; 65ꢀ55,
1-CH2OH; 124ꢀ38, 2C, C 2 and C 6; 127ꢀ95, C 4; 140ꢀ68, C 1;
143ꢀ24, 2C, C 3 and C 5. m/z 332 (M +, 80%), 314 (M ꢁ H2O,
4), 301 (M ꢁ CH2OH, 9), 275 (M ꢁ C4H9, 10), 259 (8), 234
(65), 219 (15), 204 (31), 189 (10), 173 (5), 159 (11), 135 (35),
105 (100), 91 (30), 79 (10), 71 (C5H11+, 18), 57 (C4H9+, 30),
43 (C3H7+, 48).
The
E
isomer (14h) was
C
a
clear oil (Found: M+ꢃ
,
460ꢀ4083.
34H52 requires M+ꢃ, 460ꢀ4069). ꢀmax 3019,
2956, 2926, 2854, 1596, 1512, 1465, 1378 cmꢂ1
.
ꢁH
0ꢀ88(5), t, J 7ꢀ0 Hz, 6H, 30-(CH2)5CH3 and 50-(CH2)5CH3;
0ꢀ88(9), t,
J
6ꢀ9 Hz, 3H, 400-(CH2)7CH3; 1ꢀ20–1ꢀ37, m,
22H, 30-(CH2)2(CH2)3CH3, 50-(CH2)2(CH2)3CH3 and 400-
(CH2)2(CH2)5CH3; 1ꢀ56–1ꢀ68, m, 6H, 30-CH2CH2C4H9, 50-
CH2CH2C4H9 and 400-CH2CH2C6H13
;
2ꢀ59, t, J 7ꢀ6 Hz,
4H, 30-CH2C5H11 and 50-CH2C5H11
;
2ꢀ60, t,
J
7ꢀ4 Hz,
2H, 400-CH2C7H15
7ꢀ08, d,
;
6ꢀ84, d,
J
1ꢀ2 Hz, H 40; 7ꢀ02 and
J
16ꢀ3 Hz, 1H each, H 1 and H 2; 7ꢀ14, d,
J
1ꢀ2 Hz, 2H, H 20 and H 60; 7ꢀ16, d, J 8ꢀ1 Hz, 2H, H 300
and H 500; 7ꢀ42, br d, J 8ꢀ0 Hz, 2H, H 200 and H 600. ꢁC
14ꢀ10, 3C, 30-(CH2)5CH3, 50-(CH2)5CH3 and 400-(CH2)7CH3;
22ꢀ61, 2C, 30-(CH2)4CH2CH3 and 50-(CH2)4CH2CH3; 22ꢀ67,
400-(CH2)6CH2CH3; 28ꢀ99, 2C, 30-(CH2)2CH2C3H7 and 50-
(CH2)2CH2C3H7; 29ꢀ10, 400-(CH2)4CH2C3H7; 29ꢀ27, 400-
(CH2)3CH2C4H9; 29ꢀ35, 400-(CH2)3CH2C4H9; 29ꢀ49, 400-
Oxidation of 3,5-Dioctylbenzenemethanol (7h)
A
solution of the alcohol (7h) (0ꢀ11 g, 0ꢀ33 mmol)
in dichloromethane (10 ml) was treated with pyridinium
chlorochromate (0ꢀ11 g, 0ꢀ50 mmol) at room temperature under
a nitrogen atmosphere. After 3 h the reaction mixture was
ꢁltered through Celite and puriꢁed by ꢂash chromatography on
silica gel (hexanes/diethyl ether) to give 3,5-dioctylbenzaldehyde
(7i) as a clear oil (0ꢀ11 g, 89%).
(CH2)2CH2C5H11
;
31ꢀ38, 2C, 30-CH2CH2C4H9 and 50-
CH2CH2C4H9; 31ꢀ53, 400-CH2CH2C6H13
;
31ꢀ75, 2C, 30-
(CH2)3CH2C2H5 and 50-(CH2)3CH2C2H5; 31ꢀ90, 400-(CH2)5-
CH2C2H5; 35ꢀ72, 400-CH2C7H15; 35ꢀ99, 2C, 30-CH2C5H11 and
50-CH2C5H11; 123ꢀ92, 2C, C 20 and C 60; 126ꢀ33, 2C, C 200 and
C 600; 127ꢀ96, C 40; 128ꢀ08, C 1; 128ꢀ18, C 2; 128ꢀ70, 2C, C 300
and C 500; 135ꢀ02, C 100; 137ꢀ33, C 10; 142ꢀ39, C 400; 143ꢀ15,
2C, C 30 and C 50. m/z 460 (M+, 100%), 432 (M ꢁ CH2=CH2,
2), 390 (M ꢁ CH2=CHC3H7, 10), 361 (M ꢁ C7H15, 4), 319 (4),
207 (11), 129 (4), 105 (8), 57 (C4H9+, 9), 43 (C3H7+, 12).
General Procedure for the Synthesis of 1-(3,5-Dialkylphenyl)-2-
(4-alkylphenyl)ethene
A
suspension of the 4-alkylbenzyltriphenylphosphonium
iodide (10 mmol) in tetrahydrofuran (70 ml) was treated with
butyllithium (10 mmol) at 0ꢁC. After 5 min the deep orange-red
reaction mixture was allowed to warm to room temperature
and a solution of 3,5-dialkylbenzaldehyde (5 mmol) in tetrahy-
drofuran (10 ml) was added. The mixture was stirred at
room temperature for 14 h after which time the solvents were
removed under vacuum and the residue was extracted with
dichloromethane. Workup as above (Soxhlet; hexanes) and
ꢂash chromatography on silica gel (hexanes) gave a clear oil
which consisted of a mixture of the E and Z isomers of
a 1-(3,5-dialkylphenyl)-2-(4-alkylphenyl)ethene (85–90%), and
the E and Z isomers of a 1,2-bis(4-alkylphenyl)ethene. This
mixture was separated into its components by repetitive p.l.c.
on silica gel to give analytically pure samples. Two sets of
representative spectroscopic data are listed below.
(Z)-1,2-Bis(4-octylphenyl)ethene (17d) and Its E Isomer (16d)
The Z isomer (17d) was a clear oil (Found: M+ꢃ, 404ꢀ3445.
C
30H44 requires M+ꢃ, 404ꢀ3443). ꢀmax 2956, 2926, 2854,
1596, 1512, 1464, 1384 cmꢂ1
.
ꢁH 0ꢀ87, t, J 6ꢀ5 Hz, 6H,
40-(CH2)7CH3 and 400-(CH2)7CH3; 1ꢀ22–1ꢀ35, m, 20H, 40-
(CH2)2(CH2)5CH3 and 400-(CH2)2(CH2)5CH3; 1ꢀ55–1ꢀ62, m,
4H, 40-CH2CH2C6H13 and 400-CH2CH2C6H13; 2ꢀ55, br t, J
7ꢀ9 Hz, 4H, 40-CH2C7H15 and 400-CH2C7H15; 6ꢀ51, br s, 2H,
H 1 and H 2; 7ꢀ03, br d, J 8ꢀ0 Hz, 4H, H 30, H 50, H 300
and H 500; 7ꢀ18, dt, J 8ꢀ2, 1ꢀ8 Hz, 4H, H 20, H 60, H 200
and H 600. ꢁC 14ꢀ10, 2C, 40-(CH2)7CH3 and 400-(CH2)7CH3;
22ꢀ68, 2C, 40-(CH2)6CH2CH3 and 400-(CH2)6CH2CH3; 29ꢀ28,
2C, 40-(CH2)4CH2C3H7 and 400-(CH2)4CH2C3H7; 29ꢀ34, 2C,
40-(CH2)3CH2C4H9 and 400-(CH2)3CH2C4H9; 29ꢀ49, 2C,
(Z)-1-(3,5-Dihexylphenyl)-2-(4-octylphenyl)ethene (15h)
and Its E Isomer (14h)
The Z isomer (15h) was a clear oil (Found: M+ꢃ, 460ꢀ4086.
1463, 1384 cmꢂ1. ꢁH 0ꢀ88, t, J 7ꢀ0 Hz, 6H, 30-(CH2)5CH3 and
50-(CH2)5CH3; 0ꢀ89, t, J 6ꢀ9 Hz, 3H, 400-(CH2)7CH3; 1ꢀ22–
1ꢀ35, m, 22H, 30-(CH2)2(CH2)3CH3, 50-(CH2)2(CH2)3CH3 and
C
34H52 requires M+ꢃ, 460ꢀ4069). ꢀmax 2956, 2927, 2855, 1595,
40-(CH2)2CH2C5H11 and 400-(CH2)2CH2C5H11
;
31ꢀ36, 2C,
40-CH2CH2C6H13 and 400-CH2CH2C6H13
;
31ꢀ91, 2C, 400-
(CH2)5CH2C2H5 and 400-(CH2)5CH2C2H5; 35ꢀ73, 2C, 4 -
CH2C7H15 and 400-CH2C7H15; 128ꢀ18, 4C, C 20, C 60, C 200

434
G. M. Day et al.
and C 600; 128ꢀ72, 4C, C 30, C 50, C 300 and C 500; 129ꢀ53, 2C,
C 1 and C 2; 134ꢀ75, 2C, C 10 and C 100; 141ꢀ78, 2C, C 40 and
C 4. m/z 404 (M+, 100%), 361 (M ꢁ C3H7, 2), 318 (3), 305
(M ꢁ C7H15, 20), 291 (M ꢁ C8H17, 2), 207 (22), 192 (5), 179
(4), 129 (5), 105 (8), 57 (C4H9+, 9), 43 (C3H7+, 10).
392 (M ꢁ CH2=CHCH3, 10), 350 (M ꢁ CH2=CHC4H9, 2), 336
(M ꢁ CH2=CHC5H11, 8), 315 (14), 302 (2), 237 (2), 217 (22),
203 (8), 145 (3), 133 (12), 118 (100), 105 (10), 91 (9), 69 (8),
43 (C3H7+, 10).
The E isomer (16d) was an oily wax (Found: M+ꢃ
,
Acknowledgments
404ꢀ3443.
C
30H44 requires M+ꢃ, 404ꢀ3443). ꢀmax 2954,
This work was supported by the Foundation for
Research, Science & Technology, New Zealand. We
thank Dr G. A. Dawson for helpful discussions.
2918, 2848, 1463, 1384 cmꢂ1
.
ꢁH 0ꢀ88, t, J 7ꢀ1 Hz, 6H,
40-(CH2)7CH3 and 400-(CH2)7CH3; 1ꢀ27–1ꢀ31, m, 20H, 40-
(CH2)2(CH2)5CH3 and 400-(CH2)2(CH2)5CH3; 1ꢀ57–1ꢀ64, m,
4H, 40-CH2CH2(CH2)5CH3 and 400-CH2CH2C6H13; 2ꢀ59, br
t, J 7ꢀ6 Hz, 4H, 40-CH2C7H15 and 400-CH2C7H15; 7ꢀ04, br
s, 2H, H 1 and H 2; 7ꢀ15, br d, J 8ꢀ2 Hz, 4H, H 30, H 50,
H 300 and H 500; 7ꢀ41, br d, J 8ꢀ2 Hz, 4H, H 20, H 60, H 200
and H 600. ꢁC 14ꢀ09, 2C, 40-(CH2)7CH3 and 400-(CH2)7CH3;
22ꢀ66, 2C, 40-(CH2)6CH2CH3 and 400-(CH2)6CH2CH3; 29ꢀ26,
2C, 40-(CH2)4CH2C3H7 and 400-(CH2)4CH2C3H7; 29ꢀ32, 2C,
40-(CH2)3CH2C4H9 and 400-(CH2)3CH2C4H9; 29ꢀ48, 2C,
Supplementary Data
Experimental text including spectroscopic characterization
data for the compounds [RPPh3I (R = CH3, C3H7, C4H9,
C5H11, C7H15), (1g–o), (2a,b), (3a,b), (4b), (5a,b,d,f–j), (6b–
d), (7a,c–f), (8b), (9a,b,d), (10a,b,d), (11a,b,d), (14a–g,i,j),
(15a–g,i,j), (16a–c) and (17a–c)] referred to in this paper. Copies
are available, until 31 December 2002, from the Australian
Journal of Chemistry, P.O. Box 1139, Collingwood, Vic. 3066.
40-(CH2)2CH2C5H11 and 400-(CH2)2CH2C5H11
;
31ꢀ44, 2C,
40-CH2CH2C6H13 and 400-CH2CH2C6H13
;
31ꢀ88, 2C, 400-
(CH2)5CH2C2H5 and 400-(CH2)5CH2C2H5; 35ꢀ72, 2C, 4 -
CH2C7H15 and 400-CH2C7H15; 126ꢀ29, 4C, C 20, C 60, C 200
and C 600; 127ꢀ70, 2C, C 1 and C 2; 128ꢀ70, 4C, C 30, C 50,
C 300 and C 500; 134ꢀ97, 2C, C 10 and C 100; 142ꢀ39, 2C, C 40
and C 400. m/z 404 (M+, 100%), 376 (M ꢁ C2H4, 2), 348
References
1
Zhang, Z. Y., and Lin, S. A., Polymer, 1996, 37, 3455;
Kajiyama, T., Nagata, Y., Washizu, S., and Takayanagi,
M., J. Membr. Sci., 1982, 11, 39.
Demus, D., Demus, H., and Zaschke, H., ‘Fluꢄssige Kristalle
2
(M ꢁ CH2=CHC2H5, 3), 305 (M ꢁ C7H15, 18), 291 (M ꢁ C8H17
,
in Tabellen’ (Deutscher Verlag fuꢄr Grundstossindustrie:
Leibzig 1984).
Chen, G. J., and Tamborski, C., J. Organomet. Chem.,
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2), 207 (18), 192 (5), 179 (4).
The E and Z isomers of the 1,2-bis(4-alkylphenyl)ethene
were shown to have formed by condensation of 4-
3
a
alkylbenzyltriphenylphosphonium iodide in the presence of
butyllithium. Typically, treatment of the 4-alkylbenzyltri-
phenylphosphonium iodide (10 mmol) with butyllithium (10
mmol) in tetrahydrofuran (30 ml) at room temperature for
14 h aꢃorded a mixture (3 : 2) of the E and Z isomers of the
1,2-bis(4-alkylphenyl)ethene (20–70%).
4
5
6
March, J., ‘Advanced Organic Chemistry: Reactions, Mech-
anisms and Structure’, 4th Edn (John Wiley: New York
1992).
Jukes, A. E., Dua, S. S., and Gilman, H., J. Organomet.
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3545; Cahiez, G., and Chavant, P.-Y., Tetrahedron Lett.,
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Tetrahedron, 1989, 45, 4163.
Reduction of 1-[3,5-Bis(oct-1-enyl)phenyl]-2-(4-
ethylphenyl)ethene (12)
7
A solution of the ethene (12) (0ꢀ57 g, 1ꢀ33 mmol) in
ethanol/hexanes (1:1, 90 ml) was stirred with palladium on
carbon (10%, 71 mg, 66ꢀ6 ꢂmol) under a hydrogen atmo-
sphere for 3ꢀ5 h. The mixture was then ꢁltered through
Celite and the solvents were removed under vacuum to give
1-(3,5-dioctylphenyl)-2-(4-ethylphenyl)ethane (13) as a clear
oil (0ꢀ57 g, 98%), Kugelrohr 210–215ꢁC/0ꢀ1 mmHg (Found:
8
9
C, 88ꢀ4; H, 11ꢀ6.
C
32H50 requires C, 88ꢀ4; H, 11ꢀ6%.
Olah, G. A., Narang, S. C., Balaram Gupta, B. G., and
Found: M+ꢃ, 434ꢀ3914. C32H50 requires M+ꢃ, 434ꢀ3913).
Malhotra, R., J. Org. Chem., 1979, 44, 1247; Olah, G. A.,
Husain, A., Singh, B. P., and Mehrotra, A. K., J. Org.
Chem., 1983, 48, 3667.
ꢀmax 3011, 2926, 2854, 1602, 1514, 1456, 1378, 1061 and
709 cmꢂ1
.
ꢁH 0ꢀ88, br t,
J
6ꢀ5 Hz, 6H, 30-(CH2)7CH3
and 50-(CH2)7CH3; 1ꢀ23, t, J 7ꢀ7 Hz, 3H, 400-CH2CH3; 1ꢀ23–
10
Wittig, G., and Schoꢄllkopf, U., Chem. Ber., 1954, 87, 1318;
1ꢀ38, m, 20H, 30-(CH2)2(CH2)5CH3 and 50-(CH2)2(CH2)5CH3;
Kꢄobrich, G., Angew. Chem., Int. Ed. Engl., 1962, 1, 51;
Schlosser, M., and Christmann, K. F., Angew. Chem., Int.
Ed. Engl., 1964, 3, 636; Schlosser, M., Muꢄller, G., and
Christmann, K. F., Angew. Chem., Int. Ed. Engl., 1966,
5, 667; Crombie, L., Hemesley, P., and Pattenden, G., J.
Chem. Soc., 1969, 1024; Bohlmann, F., Staꢃeldt, J., and
Skuballa, W., Chem. Ber., 1976, 109, 1586.
Speziale, A. J., and Ratts, K. W., J. Am. Chem. Soc.,
1962, 84, 854; Wheeler, O. H., and Battle de Pabon, H.
N., J. Org. Chem., 1965, 30, 1473.
Le Bigot, Y., Delmas, M., and Gaset, A., Tetrahedron Lett.,
1983, 24, 193.
Cambie, R. C., Rutledge, P. S., Tercel, M., and Woodgate,
P. D., J. Organomet. Chem., 1986, 315, 171; Cambie, R.
C., Clark, G. R., Gallagher, S. R., Rutledge, P. S., Stone,
M. J., and Woodgate, P. D., J. Organomet. Chem., 1988,
342, 315.
1ꢀ56–1ꢀ63, m, 4H, 30-CH2CH2C6H13 and 50-CH2CH2C6H13
2ꢀ54, br t, J 7ꢀ9 Hz, 4H, 30-CH2C7H15 and 50-CH2C7H15
;
;
2ꢀ62, t,
J
7ꢀ6 Hz, 2H, 400-CH2CH3; 2ꢀ81–2ꢀ92, m, 4H,
(H 1)2 and (H 2)2; 6ꢀ82, br s, 3H, and 7ꢀ11, br s, 4H,
H 200, H 300, H 500, H 600, H 20, H 40 and H 60. ꢁC 14ꢀ11, 2C, 30-
(CH2)7CH3 and 50-(CH2)7CH3; 15ꢀ56, 400-CH2CH3; 22ꢀ69, 2C,
30-(CH2)6CH2CH3 and 50-(CH2)6CH2CH3; 28ꢀ46, 400-CH2CH3;
29ꢀ31, 2C, 30-(CH2)4CH2C3H7 and 50-(CH2)4CH2C3H7; 29ꢀ48,
2C, 30-(CH2)3CH2C4H9 and 50-(CH2)3CH2C4H9; 29ꢀ51, 2C,
11
30-(CH2)2CH2C5H11 and 50-(CH2)2CH2C5H11
;
31ꢀ63, 2C,
12
30-CH2CH2C6H13 and 50-CH2CH2C6H13
;
31ꢀ93, 2C, 30-
(CH2)5CH2C2H5 and 50-(CH2)5CH2C2H5; 35ꢀ99, 2C, 30-
CH2C7H15 and 50-CH2C7H15; 37ꢀ70 and 38ꢀ14, C 1 and C 2;
125ꢀ84, 2C, C 20 and C 60; 126ꢀ14, C 40; 127ꢀ73, 2C, C 200 and
C 600; 128ꢀ35, 2C, C 300 and C 500; 139ꢀ26, C 100; 141ꢀ61, C 400;
141ꢀ67, C 10; 142ꢀ77, 2C, C 30 and C 50. m/z 434 (M+, 24%),
13